Synthesis of 2-mercaptoethanol



Patented App. 23, i963 l g w h d l 3,086,997 c arge to the reactor ThenH 8 was added until the hydroxide was all converted to hydrosulfide.This mixyg g i gg g gg i i lgfg ggfijfigg ture was then heated to 150 F,and ethylene oxide Petroleum Company, a corporation of Delaware (110g)was added over a period of 7 minutes. The

No Drawing. Filed N 7, 1961 Sen 159,632 reactlon temperature rose to 125F. and the pressure 3 Claims, ((11, 260.409) to 40 psig. After allowinga few minutes .to complete the reaction, the reactor product wasneutralized with This invention relates to a novel synthesis of2-mersulfuric acid (80 ml., 98 percent) to a pH of 3. Two captoethanol.In one of its aspects the invention relates phases were present; r tothe synthesis of 2amercaptoethanol by first inter-react- 10 Grams ingsodium hydroxide and hydrogen sulfide to form Organic phase 287 sodiumhydrosulfide and then inter-reacting the reaction Water phase 446 masswith ethylene oxide and then neutralizing t final These were separatedand an ASTM distillation on the reaction mass thus obtained.

organic phase showed that it contained approximately l l 1Zmercaptoethanol, which is valuable as a mercaptan 50 percent Water and50 percent of mater} a1 bmhng and as alctohol? g l i in above 250 F. Thedistillation end point was 328 F. prepara o wa 6r I e an p0 i L asshowing that no thiodiglycol was formed (boiling point been prepared,according to the present invention, by 0 F) reactions which can beillustrated by the following:

Example II A stainless-steel autoclave with a l-qu-art capacity was2H0CHzOHzSNa+HrSO H0CH OH SH used. Charge data on the run are asfollows.

Charge:

By proceeding according to the foregoing reactions it is possible toobtain the 2-mercaptoethanol without the formation of thiodiglycol. i gM1es Thus in one process known to me 2-mercaptoethanol and thiodiglycolare obtained by reaction of ethylene fi q percent) 3g oxide and hydrogensulfide. This can be illustrated by OH2-CHZ-0 110 2 5 the followingreactions. l

0H2 CH2+HiS HOOH2OHnSH fifigj s F (2) O Pressure,p si2 25-45. gf a gg gHOCH2CH2SH+CH2 C 2- HOCHl H2SC 2 HzOH H2804 (cohcentmted) added H 80 Itis an object of this invention to provide a novel synp 3. thesis forZ-mercaptoethanol. It is a further object of 3 13553353 F 2%: thisinvention to provide a method for producing Z-rner- Distillation g 1Organic p ASTM 133M760- captoethanol without the formation ofthiodiglycol. E (2 9) Other aspects, objects and the several advantagesof Nozwater phase this invention are apparent from a study of thisdisclosure .and the appended claims.

According to the present invention there is provided a process for thesynthesis of Z-mercaptoethanol which comprises inter-reacting sodiumhydrosulfide and ethylene loxide at an elevated temperature, and aftercompletion g g gf gg 1 of the reaction thus obtained, neutralizing thereaction of 1\l0 101ganic phase 144 g mass and recoveringZ-mercaptoethanol from the neu Theoreticalyield 195 tralized mass thusobtained. In a now preferred form 1 Required to add. the ethylene oxide.of the invention sodium hydroxide and water are charged to a reactor.Then hydrogen sulfide is added to convert It W111 be noted that m thefiol'egmPg examples there the sodium hydroxide to hydrosulfide. Themixture thus a P absence of fy 111 the obtained is heated toapproximately 150 F. Ethylene Q T1115 Shows that thlodl'glycol, thebolllng Polllt oxide is then added over a period of a few minutes. ofWhlch, as stated 15 was not formed- The reaction temperature andpressure are allowed to When the alkali metal hydrosulfide and ethyleneoxide rise and after a f minutes, f completion of the are reacted thetemperature is elevated. One skilled in action, the reaction product isneutralized with sulfuric art havlng Studled this dlsdosuIe W111detelmlne a acid to a PH of 3, obtaining two phases, namely an Opdesirable temperature. However, the results which have m Phase and awater phase. been obtained and which have been set out herein can Onseparating the phases and distilling the organic Obtamed by Fl y Oxideto the sodlum yphase a distillation end point f can bedrosulfide-zcontalnlng mass at a temperature in the range tained showingthat no thiodiglycol has been formed. of 125 to Thiodiglycol boils at 5R Reasonable variation and modification are possible It will be evidentto one skilled in the art reading this the fmgomg 1186mm and tdisclosure that other alkali metal hydroxides can be flPPend6d clams mthe mventlon essence, Whlch used and that neutralization can be effectedwith other 15 P has been Prepared Wlthout the acids formation ofthlodlglycol by inter-reacting sodium hydro- Example I sulfide andethylene oxide and then converting the reaction mass thus obtained byneutralizing the same with A run was made in a 1-liter stainless-steelreactor. sulfuric acid, ultimately obtaining from the final reactionSodium hydroxide g.) and water (400 g.) were mass the 2-mercaptoethanol.

I claim:

1. A method of preparing Z-rne-rcaptoethanol which comprisesinterreactin g sodium hydrosulfide and ethylene oxide and thenneutralizing the reaction mass thus obtained.

2. A process of preparing 2-mercaptoethano1 which comprisesinterreacti'ng sodium hydrosulfide and ethylene oxide at a temperaturein the range 1i25-250 F. and then neutralizing the reaction mass thusobtained sulfiuri'c" acid following which a final mass thus obtained issubjected to a recovery process fior recovering 2- me'rcaptoethanol. v

3'. A process for the preparation of 2-1meroaptoethano1 which comprisescharging sodium hydroxide, water and 4 hydrogen sulfide into a reactionzone to produce therein sodium hydrosulfide, heating the sodiumhydrosulfide thus produced to a temperature of approximately 150 F.,then adding ethylene oxide and then neutralizing the final reaction massthus obtained with sulfuric acid and recovering 2mercaptoethanol fnornthe neutralized final reaction mass.

References Cited in the file of this patent FOREIGN PATENTS France Aug.22, 1934 OTHER REFERENCES Sjoberg- Ber. Deu-t. Chem. 74, 64-72 (1941).

2. A PROCESS OF PREPARING 2-MERCAPTOETHANOL WHICH COMPRISES INTERREACTING SODIUM HYDROSULFIDE AND ETHYLENE OXIDE AT A TEMPERATURE IN THE RANGE 125-250*F. AND THEN NEUTRALIZING THE REACTION MASS THUS OBTAINED WITH SULFURIC ACID FOLLOWING WHICH A FINAL MASS THUS OBTAINED IS SUBJECTED TO A RECOVERY PROCESS FOR RECOVERING 2MERCAPTOETHANOL. 